change default setting to what I want for Win 8

I use note pad for my txt files yet win 8 has set it as word pad by default. When I trying remove the check box for txt in word pad, it refused to allow me to do that. At the same time, I cannot edit my raw html pages on the server as the pages come up as either IE or FF program that open the real view of the page that can not be edit live as it impossible to do so in the first. Even if I try...